Ionic polymers (ionomers) with interesting characteristics are emerging as important commercial polymers. Ionomers have
the unique ability to behave as cross-linked materials at ambient temperatures and to melt and flow at elevated temperatures like
thermoplastics. The complex permittivity and conductivity of a class of ionomers at microwave frequencies are determined
using the cavity perturbation technique and the results are presented.

The detection of buried objects using time-domain freespace
measurements was carried out in the near field. The location of a
hidden object was determined from an analysis of the reflected signal.
This method can be extended to detect any number of objects. Measurements
were carried out in the X- and Ku-bands using ordinary rectangular
pyramidal horn antennas of gain 15 dB. The same antenna was
used as the transmitter and recei er. The experimental results were
compared with simulated results by applying the two-dimensional
finite-difference time-domain(FDTD)method, and agree well with each
other. The dispersi e nature of the dielectric medium was considered for
the simulation.

In the medical field, microwaves play a larger role for treatment than diagnosis. For the detection of diseases by microwave methods, it is essential to know the dielectric properties of biological materials. For the present study, a cavity perturbation technique was employed to determine the dielectric properties of these materials. Rectangular cavity resonators were used to measure the complex permittivity of human bile, bile stones, gastric juice and saliva. The measurements were carried out in the S and J bands. It is observed that normal and infected bile have different dielectric constant and loss tangent. Dielectric constant of infected bile and gastric juice varies from patient to patient. Detection and extraction of bile stone with possible method of treatment is also discussed.

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A novel cavity perturbation technique using coaxial cavity resonators for the measurement of complex permittivity of liquids is presented. The method employs two types of resonators (Resonator I and Resonator II). Resonator I operates in the frequency range 600 MHz-7 GHz and resonator II operates in the frequency range 4 GHz-14 GHz. The introduction of the capillary tube filled with the sample liquid into the coaxial resonator causes shifts in the resonance frequency and loaded Q-factor of the resonator. The shifts in the resonance frequency and loaded Q-factor are used to determine the real and imaginary parts of the complex permittivity of the sample liquid, respectively. Using this technique, the dielectric parameters of water and nitrobenzene are measured. The results are compared with those obtained using other standard methods. The sources of errors are analyzed.

This paper presents the design of a new type of corner reflector (CR) antenna and the experimental investigation of its radiation characteristics. The design involves the addition of planar parallel periodic strips to the two sides of a CR antenna. The position, angular orientation, and number of strips have a notable effect on the H-plane radiation characteristics of the antenna. Certain configurations of the new antenna are capable of producing very sharp axial beams with gain on the order of 5 dB over the square corner reflector antenna. A configuration that can provide symmetric twin beams with enhanced gain and reduced half-power beam width (HPBW) is also presented.

HIV/AIDS is one of the most destructive epidemics in
ever recorded history claims an estimated 2.4 –3.3 million lives every
year. Even though there is no treatment for this pandemic Elisa and
Western Blot tests are the only tests currently available for detecting
HIV/AIDS. This article proposes a new method of detecting HIV/AIDS
based on the measurement of the dielectric properties of blood at the
microwave frequencies. The measurements were made at the S-band of
microwave frequency using rectangular cavity perturbation technique
with the samples of blood from healthy donors as well as from HIV/AIDS patients. An appreciable change is observed in the dielectric properties
of patient samples than with the normal healthy samples and these
measurements were in good agreement with clinical results. This measurement
is an alternative in vitro method of diagnosing HIV/AIDS using microwaves.

This article reports a new method of analyzing pericardial
fluid based on the measurement of the dielectric properties at microwave
frequencies. The microwave measurements were performed by
rectangular cavity perturbation method in the S-band of microwave frequency
with the pericardial fluid from healthy persons as well as from
patients suffering from pericardial effusion. It is observed that a remarkable
change in the dielectric properties of patient samples with the
normal healthy samples and these measurements were in good agreement
with clinical analysis. This measurement technique and the method
of extraction of pericardial fluid are simple. These results give light to
an alternative in-vitro method of diagnosing onset pericardial effusion
abnormalities using microwaves without surgical procedure.

Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) bioceramic and
chitosan (poly [( -1-4) D-glucosamine]) biopolymer show good biocompatibility
in vivo. They have biological origin and show excellent interactions
with microwave. Microwave study of HAp made using different
drying techniques and their composites with chitosan in the ISM band is
presented. Pastes are made using HAp and chitosan with different ratios
of mixing. The dielectric properties of this composites match with that of
human fat, collagen tissues. Some of the compositions exhibit dielectric
property close to that of natural bone. This makes them more
biocompatible and better substitutes for natural bone. Thus composite
bioceramics can be considered as phantom model constituents for
imaging purposes. Their dielectric properties prove that they are
biocompatible.

This article reports a new in vitro bile analysis based on
the measurement of the dielectric properties at microwave frequencies.
The measurements were made using rectangular cavity perturbation
technique at the S-band of microwave frequency with the different samples
of bile obtained from healthy persons as well as from patients. It is
observed that an appreciable change in the dielectric properties of patient’s
samples with the normal healthy samples and these measurements
were in good agreement with clinical analysis. These results prove an
alternative in-vitro method of detecting bile abnormalities based on the
measurement of the dielectric properties of bile samples using microwaves
without surgical procedure.

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Conducting polymers are excellent microwave absorbers
and they show technological advantage when compared
with inorganic electromagnetic absorbing materials,
being light weight , easily processable, and the ability
of changing the electromagnetic properties with nature
and amount of dopants, synthesis conditions, etc. In this
paper we report the synthesis, dielectric properties, and
expected application of conducting composites based
on polyaniline (PAN). Cyclohexanone soluble conducting
PAN composites of microwave conductivity 12.5 S/m
was synthesized by the in situ polymerization of aniline
in the presence of emulsion grade polyvinyl chloride. The
dielectric properties of the composites, especially the
dielectric loss, conductivity, dielectric heating coefficient
, absorption coefficient, and penetration depth,
were studied using a HP8510 vector network analyzer.
The microwave absorption of the composites were studied
at different frequency bands i.e, S, C, and X bands
(2-12 GHz). The absorption coefficient was found to be
higher than 200 m -' and it can be used for making microwave
absorbers in space applications